Machines such as, for example, dozers, motor graders, wheel loaders, wheel tractor scrapers, and other types of heavy equipment are used to perform a variety of tasks at a worksite. Autonomously and semi-autonomously controlled machines are capable of operating with little or no human input by relying on information received from various machine systems. For example, based on machine movement input, terrain input, and/or machine operational input, a machine can be controlled to remotely and/or automatically complete a programmed task. By receiving appropriate feedback from each of the different machine systems during performance of the task, continuous adjustments to machine operation can be made that help to ensure precision and safety in completion of the task. In order to do so, however, the information provided by the different machine systems should be accurate and reliable. Parameters indicative of machine motion, e.g., velocity and change in position of the machine, are parameters whose accuracy may be important for control of the machine and its operation.
Some exemplary systems determine velocity and change in position based on vision systems, utilizing methods known as visual odometry. For example, an exemplary system that may be used to determine changes in position is disclosed in U.S. Pat. No. 8,238,612 to Susca et al. that issued on Aug. 7, 2012 (the '612 patent). The system in the '612 patent utilizes two optical cameras (stereo image) to obtain images at two different times. Based on changes between the images from the two cameras at different times, the system determines the translational and rotational movement of a mobile machine on which the cameras are mounted. In another embodiment, the system in the '612 patent utilizes a Light Detection and Ranging (LIDAR) device to obtain a 3D image of a scene at two different times. Based on changes between the LIDAR-based images, the system determines the translational and rotational movement of a mobile machine on which the LIDAR device is mounted.
Although the system of the '612 patent may be useful for determining various motions of a mobile machine, in some situations, a system which utilizes a single camera is desirable. For example, in the interest of saving initial costs and maintenance costs, a machine may be outfitted with only a single camera. A single camera does not provide the stereo image that is required by the system of the '612 patent. Furthermore, the LIDAR-based system of the '612 patent may not be suitable for uniform terrain.
The disclosed motion determination system is directed to overcoming one or more of the problems set forth above and/or other problems of the prior art.